Coal mining machine



April 16, 1935. F. B. YINGLING COAL MINING MACHINE Filed Dec. 3, 1932 s Sheets-Sheet 1 HTTOEIYEXS April 16, 1935. F. B. YINGLING COAL MINING MACHINE Filed Dec. 3, 1932 8 Sheets-Sheet 2 mm NTOE arrale/wivfi April 16, 1935. F. BIYINGLING 1,998,180

COAL MINING MACHINE Filed Dec. 5, 1932 8 Sheets-Sheet 5 April 1935- Q F. B. YINQGLING I 1,998,180

' QOAL' MINING MACHINE Filed Dec. 3, 1932 8 Sheets-Sheet 4 :1 \s r w E E N h 2 n April 16, 1935. F. B. YINGLING COAL MINING MACHINE Filed Dec. 5, 1932 8 Sheets-Sheet 5 I April 16-, 1935.

F. B. YINGLING 1,998,180

COAL MINING MACHINE Filed Dec. 3, 1952 v s Sheets-Sheet 6 'F. B. YINGLING- poAL MINING ivIAcHINE Afiril 16, 1 935; 1,998,180

Filed Dec. 5, 1932 8 Sheets-Shei 7 ATTOE/VEVJ A ril 16, 1935. F. B. YINGLING 1,998,180

COAL MINING MACHINE Filed Dec. 5, 1932' 8 Sheets-Sh eet 8 Patented Apr. 16, 19535 UNITED STATES PATENT OFFICE COAL MINING MACHINE Application December 3, 1932, Serial No. 645,568

28 Claims.

This invention relates to improvements in coal mining machines, and has forrits object to provide such a machine in which the cutting blade may be rotated and may be moved in a circular path from one side of atruck carrying the blade, around the front of, the truck and to the'other side of the truck. The blade may also be moved in an arcuate path from a point in front of the truck carrying the blade to a point above the truck, and in line therewith.

It is also an object of this invention to provide a coal mining machine with a blade, and means for moving the blade so that a substantially rectangular cut may be made. The blade may be operated so that it will cut a semi-circular slot at any angle with relation to the plane upon which the machine is resting, from one side of the machine to the other, extending over the machine.

It is also an object of this invention to provide, in connection with a cutter blade, an extensible arm for supporting the blade upon a truck or chassis, the extensible arm being composed of telescopic members, one of which not only moves longitudinally of the other but rotates with respect thereto so that the blade may be given any angular position with relation to the truck or chassis supporting the blade by means of the arm.

It is a further object of this invention to provide, in connection with a coal mining machine, a telescopically extensible arm so supported on a truck that the arm may swing i'na vertical path and in ahorizontal path, so that the blade may be operated in any position from one side of the truck, around to the other side of the truck, and from a point above the truck to a point adjacent the horizontal trackway supporting the truck.

It is a further object to provide, in connection with a coal mining machine comprising a truck and a blade connected to the truck by a telescopic arm, means for operating the blade located on the truck and connected to the arm by means of suitable operating mechanism.

These and other advantages will appear from the following description taken in connection with the drawings.

Referring to the drawings:

Figure 1 is a diagrammatic view showing an arcuate path cut by the blade, extending from a point in front of the truck to a point above and parallel with the truck. This view also shows diagrammatically a circular, horizontal cut made by the blade above the truck, with a part of this 1 cut extending in front of the truck.

Figure 2 is a diagrammatic view showing the various positions the blade may assume with relation to the truck. This view shows the blade in a horizontal position, a vertical position and a second-horizontal position, extending over the top of the truck.

Figure 3 is a diagrammatic view showing the various cuts that can be made by the blade at points above the truck.

/ Figure 4 is a diagrammatic view showing various forms of cuts that may be made by the blade in a path horizontal to the plane of the truck support. 1

Figure 5 is a view showing other forms of cuts that may be made by the blade in a path horizontal to the support of the truck.

Figure 6 is a top plan view of the coal mining machine.

Figure '7 is a side elevation of the coal mining machine.

Figure 8 is a longitudinal, vertical section 7 through the truck, showing the drive mechanism for transporting the truck, the motor and gear mechanism for operating the cutter blade, together with the motor for giving the truck yoke lateral movement.

Figure 9 is a top plan view of the truck yoke.

Figure 10 is a side elevation of the truck yoke. Figure 11 is a section on the line HIl 01.

Figure 10.

Figure 12 is a horizontal, longitudinal section through the telescoping arm.

Figure 13 is a vertical, longitudinal section through the telescoping arm.

Figure 14 is a section on the line I l-l4 Figure 13.

Figure 15 is a section on the line l5-I5 of Figure 14.

Figure 16 is a section on the line Iii-l6 of Figure 13.

Figure 17 is a section on the line |'|-l'| of Figure 16.

Figure 18 is a section on the line l8l8 of Figure 13.

Figure 19 is a section on the line |9--l9 of Figure 18.

Figure 20 is a top plan view of the cutter yoke, cutter head and one end of the cutter blade.

Figure 21 is a section on the line 2l-2l of Figure 20,

Figure 22 is a top plan view of the cutter blade with parts thereof broken away.

Figure 23 is a top plan view of the cutter yoke. Figure 24 is a section on the line 24-44 of Figure 23.

Figure 25 is a top plan view of the cutter head.

Figure 26 is a section on the line 26-26 of Figure 25.

Figure 27 is a top plan view of the telescopic sleeve forming part of the telescoping arm.

Figure 28 is a side elevation of the sleeve shown in Figure 27, with a part thereof broken away.

The present coal mining machine is adapted to travel along a horizontal trackway A. The truck which forms the supporting element of the machine is indicated by the numeral I, and has thereon wheels 2 which engage a track for transporting the mining machine during the process of operation or transportation. For driving the transporting gear there is provided a motor 3, which is connected to the wheels by suitable intervening gear mechanism, forming no part of this invention Located centrally of the truck is a motor 4, which has the usual motor shaft with a pinion 5 thereon engaging an internal gear 9 mounted upon a shaft 1 supported in suitable bearings on supports 8, forming part of the frame of the truck. The gear 6 is located on one end of the shaft 1, while on the other end of this same shaft is a bevel gear 9 which meshes with a bevel gear -12- fixed to a shaft l I, supported in suitable bearings formed in ahousing 19. This housing incloses the bevel gear 9, the bevel gear I2 and most of the shaft II. On the upper end of the shaft ll, without thehousing i9, is a bevel'gear [3.

The body of the truck in its upper part a forwardly extending arm 14, and in its lower part a forwardly extending lower arm l5. These arms have holes 16 which are in alignment with the shaft ll. These arms [4 and I5 support a truck yoke 11, which has an upper arm 18 pivoted to the upper arm 14, and a lower arm 19 pivoted to the lower arm l5.

For the purpose of pivoting these arms there is provided in eaoh. of the arms l3 and 19 a hole 20, which aligns with the holes I6 for-receiving some suitable connecting pin or shaft. Extending rearwardly from the truck yoke is a bracket 2|, which forms a semi-circular worm gear used for rotating the truck yoke about its pivots 20a. The teeth of the worm gear 2| are engaged by a worm 22 located on a shaft 23, supported by suitable brackets 24;

On the shaft 23 is a bevel gear 25 engaged by a bevel gear 26 located on one end of the shaft of a motor 21. This motor is suitably supported on the frame of the truck, and through the shaft and associated gear structure the truck yoke is rotated about its pivots 26a. The pivots 20a are vertically disposed so that the truck yoke swings about its pivots in a horizontal plane and carries with it all of the operating mechanism.

On the truck yoke between the arms [8 and I9 is a housing 28, which has extending therethrough a shaft 29 supported at each end by a bearing formed in the walls of the housing and as part of the truck yoke. On this shaft within the housing is a bevel gear 30 adapted to engage the bevel gear 13 and be driven thereby from the motor 4. On this shaft 29 adjacent the bevel gear 39 is a spur gear 3| meshing with a second spur gear32 located in a housing 33, forming an extension of the housing 28. This spur gear 32 is supported in the housing 33 by means of a shaft 34, to which it is attached for rotation therewith. This shaft is supported in forwardly extending, spaced arms ,35, forming parts of the truck yoke.

These arms 35 are semi-circular in shape and have on their circular peripheries teeth 35. The shaft 34 is located in bearings in these arms, at the center of the are forming the periphery thereof and on which the teeth 36 are located. The truck yoke is supported on the truck by means of the pivots 20a, and supports a telescoping arm on the shaft 34. This arm is composed of an outer sleeve 31, which has on its rear end an extension 38 forming a casing 40. Through this casing the shaft 34 extends by means of holes 4|, located in arms 39. The lower of these arms is spaced from the housing 40 to provide a space 42, in which is received the housing 33 inclosing the gear 32 on the shaft 34. On this shaft 34, within the casing 40, is a bevel gear 43.

When the telescoping arm is assembled on the truck yoke the arms 39 fit in between the arms 35, with the shaft 34 extending through suitable holes in the arms 35. The bevel gear 43 meshes with a bevel gear 44, located on a drive shaft 45 which extends longitudinally through the telescoping arm and is supported at one end by means of a bearing 46 adjacent the gear 44. The drive shaft 45 is hollow and has splined therein a second drive shaft 41 adapted to be rotated by the shaft 45, and to move longitudinally thereof.

The forward end of the shaft 41 is journalled in bearings 48 and 49 located in the front end of a sleeve 50, which is telescopically arranged within the sleeve .31 for longitudinal movement therein. The shaft 41 is held against longitudinal movement with relation to its bearings by means of a stop ring 5|, suitably attached to the shaft at the rear of the bearing 49 by means of a bevel gear 52, attached to the shaft 41 in front of the bearing 49.

Located within the sleeve 50 is a third sleeve 53, splined to the sleeve 50 by means of a spline 54 so that these two sleeves may move longitudinally with relation to each other, but rotate together. On the rear end of the sleeve 53 is a worm gear 55 located in a housing 56 formed on the rear end of the sleeve 31 and adjacent the casing 40.

For the purpose of rotating the gear 55 there is provided on one .side of the sleeve 31 a motor 51, which has a shaft 58 with a gear 59 thereon meshing with a gear 60, located on a shaft 3| supported in suitable bearings in the housing 56. On this shaft 6| is a. worm 62 which meshes with the teeth of the worm gear 55 for causing the rotation of the worm gear 55 and the sleeve 50. By means of this motor and the worm gear 55 the sleeve 50 may be rotated within the sleeve 31 so that the blades supported on the front end of the sleeve 50 may be given any angular position.

There is also suitably supported on one side of the sleeve 31 an extension motor 63, which has the usual shaft with a worm 64 thereon, engaging a worm gear 65 located in a housing 66 and on a shaft 61. On this shaft 61 is a pinion 68 which engages a rack bar 69 located in a longitudinally disposed slot 10 formed in the sleeve 31.

On the rear end of the rack bar 69 1s a ring H which fits around the rear end of the sleeve 59, in a slot 12. This slot and ring construction permits the free rotation of the sleeve 59 within the sleeve 31 when the motor 53 is operated to rotate the pinion 6B engaging the rack bar 69. The direction of longitudinal movement of the sleeve 5!! depends upon the direction of rotation of the motor 63 and the shaft 61.

There is also located on the sleeve 31 an elevating motor I3, which has the usual motor shaft with a bevel gear I4 mounted on the end thereof and supported in a housing I5 suitably attached to and supported by the sleeve 31. This gear I4 meshes with a bevel gear I6 located on one end of a shaft 71. On the other end of this shaft I1 is a worm I8 which engages a worm 79 located in a housing 80 and one. shaft 8| extending transversely beneath the sleeve 31, and supported by means of bearings 8Ia. On each end of this shaft BI is a pinion 82. These pinions engage the teeth 36 formed on the arms for elevating the telescoping arm or lowering it about the shaft 34.

The bevel gear 52 on the forward end of the shaft 41 engages a bevel gear 83 located on a shaft 84 journalled in arms 85 extending from the front end of the sleeve 56. There is also provided on this shaft 84, adjacent one of the arms 85, a spur gear 86. Supported in a suitable housing provided therefor in the front end of the sleeve 59 is a motor 87 for adjusting the cutter head.

On the free end of the motor shaft there is a bevel gear 88 in mesh with a similar bevel gear 89 on a shaft 89a. The shaft 89a drives through suitable gears a shaft 99 which carries pinions 9| adapted to engage with teeth 94 formed on rearwardly extending brackets 93 formed on a cutter yoke 92. This cutter yoke is pivoted on the shaft 84, with the brackets 93 engaging the ends thereof so that the teeth on the brackets may be engaged by the pinions QI located on the ends of the shaft 99. Extending forwardly from the cutter yoke is a forward bracket 95, which has teeth 96 thereon.

The rotation of the shaft 96 causes the cutter yoke to rotate about the shaft 84. The spur gear 86, located on the shaft 84, engages a spur gear 9'! located on a shaft 98 journalled in the cutter yoke in advance ofand parallel with the shaft 84. On this shaft 98 is a bevel gear 99, which meshes with a bevel gear I 91.

Suitably attached to the cutter yoke is a cutter head I00, which has an upper arm I6 I and a lower arm I92. To these arms the cutter yoke is journailed by means of a diagonally disposed bracket I93 and a pivot pin I94 passing through this bracket and the lower arm I62, and by means of a bearing I65 passing through the upper arm and a horizontal part of the cutter yoke. Extending through the bearing I65 is a shaft I66, which has on its lower end a gear Iil'I, which meshes with the bevel gear 99, and on its upper end above the cutter head a sprocket I68.

In the forward end of the cutter head is a vertically disposed shaft I69, suitably journalled in bearings therein, with a pinion H6 thereon engaging the teeth 96 on the periphery of the forward bracket 95, concentric with the shaft I96 and the pivot I64. On the lower end of this shaft I69 is a worm gear II I engaged by a worm shaft F2 of a motor I I3. The operation of this motor for rotating the shaft I69 will cause the horizontal swinging of the cutter blade, which is supported on the cutter head I611.

The cutter bar I I4 is shown in plan in Figure 22 and consists of spaced arms I I 5 adapted to fit on opposite sides of a lug H6 on top of the cutter head I99. In the rearward ends of the spaced arms are elongated holes II'I adapted to receive bolts I I8 for fastening the cutter bar to the cutter head so that the cutter bar may be adjusted longitudinally for taking up slack in the cutter chain.

The cutter bar is held in adjusted position by means of a cross arm I I9 and a bolt I26 passing through this arm into the lug H6. The bolt is adjusted with relation to the cross arm I I9, through which it extends by means of nuts I2 I.

On the forward end of the cutter bar is a sprocket I22. Around this sprocket and the sprocket I08 is a sprocket chain I23, on which are located cutter teeth I24. The tension of this chain may be adjusted by means of the bolt I29.

The truck yoke swings in a horizontal plane about its point of pivot on the arms I4 and I5. The telescoping arm swings in a vertical plane about its point of pivot on the truck yoke. The telescoping arm consists of a sleeve pivoted about the truck yoke and a sleeve longitudinally movable within the first-named sleeve and adapted to rotate therein. This second sleeve supports the cutter on its forward end, which is adjustable with relation thereto, both laterally and vertical- 1y.

The cutter bar may assume any position with relation to the telescoping arm, from an alignment therewith to a position at right angles thereto, on either side thereof, or vertically with respect thereto. The telescoping arm may be adjusted with relation to the truck yoke so that it may have any position from a horizontal position to a vertical position. When the telescoping arm is in a vertical position the cutter bar may swing around in a horizontal plane, or it may swing into any position from a horizontal plane to a position over the arm. It is therefore obvious from the connections between the various parts that the cutter blade can be given almost any position desired, in front of, to one side of or above the truck.

The operation of the cutter chain is caused by the motor 4, through the internal gear 6, the bevel gear I3 engaging the bevel gear 39, which through the shaft 29 and the spur gear SI drives the spur gear 32 mounted upon the shaft 34. Through the shaft 34 the gear 43 operates the gear 44 upon the shaft 4-5, which has a sliding and operative connection with a second shaft 47 journalled in the front end of the sleeve 56.

, On the front end of the shaft 4? is the gear 52, which engages and operates the gear 83 on the shaft 84. The shaft 84, through suitable gearing, operates the shaft Hi6, through the gear M1. The shaft I66 carries the sprocket operating the cutter chain.

The various gears forming parts of the connecton between the internal gear 6 and the sprocket are located on shafts about which the various elements are pivoted so that any change in the direction of the truck yoke, the telescoping arm or the cutter bar will not affect the operation of the drive mechainsrn for the cutter chain.

It will be observed that the axis of the gear I3 is in line with the pivotal connection between the truck and the truck yoke. The gear 43 is on the shaft 34, which forms the pivotal connection between the truck yoke and the telescoping arm and shaft 84 forms the pivotal connection between the sleeve 50 and the cutter yoke, while the shaft I96 on the gear I97 is located to form a pivotal connection between the cutter yoke and the cutter head. It is therefore obvious that any change in the direction of any part of the coal cutter would have no effect upon the operation of the drive for the cutter chain.

In Figures 1 to 5, inclusive there are shown diagrammatically the various cuts that may be made by the blade. The line b-cic shows the range of a kerf formed by swinging the cutter bar and the arm from a horizontal or substantially horizontal position through an arc b-c, when the arm and the cutter bar are in vertical position. From the vertical position the cutter bar may be swung on its pivot at the upper end of the telescoping arm to a horizontal position, with the free end of the bar at the point a. Instead of swinging the cutter bar back over the truck it may be swung on its pivot at the front or the telescoping arm through the are b--c, or the cutter bar may be rotated through the rotation of the sleeve 50 so as to cut a circular kerf having the diameter ac.

The various overhead movements of the cutter bar are illustrated in Figures 1, 2 and 3. In Fig ures 4 and 5 the horizontal movements of the cutter bar are illustrated. In Figure 4 the cutter bar is illustrated as moving from a horizontally disposed position in front of the truck to both sides. The are f--g-h is semi-circular.

When the arm and the cutter bar assume a laterally disposed position with the ends thereof at either or it, the cutter car may be swung on its pivot at the end of the telescoping arm, around to a line parallel with side of the truck, through either the arc F's-i or the arc --i. The cutter when it extends laterally from the truck may cut a vertical kerf on the lines i-y', one at each side of the truck. Rectangular cuts may be made vertically or horizontally by properly operating the cutter bar and at the same time moving the inner sleeve within the outer sleeve 3?. A rectangular kerf may be cut by arranging the cutter bar at right angles to the arm and extending or contracting the These cuts may be made in various positions in regard to the arm, laterally, above it or at any point between a lateral kerr" and a ver ical keri.

It will be understood that I desire to comprehend within my invention such modifications as come within the scope of my claims and my invention.

thus fully described my invention, what I claim as new and desire to secure by Letter Patent is:

1. In combination, chassis, means for driving a coal cutter, a coal cutter, an extensible arm supporting said coal cutter and r ounted on said chassis, means within. the ext-e .cl arm for rotating said arm, and means ciated therewith for connecting a power source to the cutter to operate it.

2. In combination, a chassis, means for driving a coal cutter, a coal cutter, an extensible arm supporting said coal cutter and moun ed on said chassis, means within the extensible arm for rotating said arm, means associated therewith for connecting a power source to the cutter to operate it, and means to adjust the angular position of said extensible arm with respect to the chassis.

3. In combination, a chassis, means for driving a coal cutter, a coal cutter, an extensible arm supporting said coal cutter and mounted on said chassis, a sleeve within the extensible arm for rotating said arm, means associated therewith for connecting a power source to the cutter to oper" ate it, and means to adjust the angular position or said extensible arm with respect to the chassis in vertical and horizontal planes.

l. In combination, a chassis, means for driving a coal cutter, a coal cutter, an extensible arm supporting said coal cutter and mounted on said chassis, means associated therewith for connecting a power source to the cutter to operate it, means to adjust the angular position of said extensible arm with respect to the chassis in vertical and horizontal planes, and means within the extensible arm to rotate said arm with the cutter with respect to said chassis.

5. In combination, a chassis, means for driving a coal cutter, a coal cutter, an extensible arm supporting said coal cutter and mounted on said chassis, means associated therewith for connecting a power source to the cutter to operate it, means to adjust the angular position of said extensible arm with respect to the chassis in vertical and horizontal planes, means to rotate said arm with the cutter with respect to the chassis, and means to angularly adjust in a vertical plane said cutter with respect to said arm.

6. In combination, a chassis, means for driving a coal cutter, a coal cutter, an extensible arm supporting said coal cutter and mounted on said chassis, means associated therewith for connecting a power source to the cutter to operate it, means to adjust the angular position of said extensible arm with respect to the chassis in vertical and horizontal planes, means to rotate said arm with the cutter with respect to said chassis, means to angularly adjust in a vertical plane said cutter with respect to said arm, and means to angularly adjust said cutter in a horizontal plane with respect to said arm.

"I. In combination, a chassis, a swinging bracket on a vertical axis, a sleeve pivoted thereon, an extensible arm mounted therein, a cutter head mounted on said arm carrying a cutter, means on said chassis, bracket, sleeve and arm and cutter head adapted to drive said cutter irrespective of its position with respect to said chassis, means to rotate said sleeve and arm with respect to one another, and means to adjust the angular position of said cutter with respect to the cutter head.

8. In combination, a chassis, a swinging bracket on a vertical axis, a sleeve pivoted thereon, an extensible arm mounted therein, a cutter head mounted on said arm carrying a cutter, means on said chassis, bracket, sleeve and arm and cutter head adapted to drive said cutter irrespective of its position with respect to said chassis, means to rotate said sleeve and arm with respect to one another, means to adjust the angular position or" said cutter with respect to the cutter head, and means to adjust the angle of the cutter head with respect to the arm.

9. In combination, a chassis, means for driving a. chassis, a power means mounted on the chassis, a bracket adapted to swing on a vertical axis, a sleeve pivoted on said bracket on a horizontal axis, a telescoping arm mounted in said sleeve, means to move the arm in and out of the sleeve, means to rotate the arm in the sleeve, a cutter head mounted on the end of the arm on a horizontal axis, a cutter pivoted on the cutter head on a vertical axis, means to adjust the head on the arm and the cutter on the head, and means connecting the power means on the chassis to said bracket, a sleeve, arm and head to operate the cutter irrespective of its position with respect to the chassis.

10. In a coal mining machine, in combination with a truck, an arm pivoted at one end to the truck and a cutter bar pivoted to the other end of the arm, said arm being composed of an outer member and an inner member rotatably mounted in the outer member, and a sleeve in the inner member positioned by the outer member for rotating the inner member.

11. In a coal mining machine, in combination with a truck, an arm supported at one end by the truck, a cutter bar attached to the other end of the arm, said arm being composed of an outer member and an inner member mounted in the outer member, a sleeve in the inner member positioned by the outer member for rotating the inner member, and means mounted on the outer member for rotating the sleeve and thereby the inner member.,

12. In a coal mining machine, in combination with a truck, a telescoping arm composed of an outer member and an inner member supported at one end by the truck, a cutter on the other. end of the arm, and means mounted on the outer member for moving the inner member longitudinally of the outer member, said means including a rack and a pinion, and means on the rack for engaging the inner member.

13. In a coal mining machine, in combination with a truck, a telescoping arm composed ofan outer member and an inner member supported at one end by the truck, a cutter on the other end of the arm, and means mounted on the outer member for moving the inner member longitudinally of the outer member, said means including a rack and pinion and a ring on the rack engaging the inner member.

14. In a coal mining machine, in combination with a truck, a telescoping arm composed of an outer member and an inner member supported at one end on the truck, a cutter on the other end of the arm, means mounted on the outer member for moving the inner member longitudinally of the outer member, said means including a rack and pinion and a ring on the rack engaging the inner member, and means for rotating the inner member in the outer member.

15. In a coal mining machine, in combination with a truck, a telescoping arm composed of an outer member and an inner member supported at one end on the truck, a cutter on the other end of the arm, means mounted on the outer member for moving the inner member longitudinally of the outer member, said means including a rack and pinion and a ring on the rack engaging the inner member, and means for rotating the inner member in the outer member, said lastnamed means including a gear supported by the outer member and operatively connected to the inner member.

16. In a coal mining machine, in combination with a truck and a cutter, an arm for supporting the cutter on the truck, said arm comprising an outer sleeve and an inner sleeve, a sleeve within and splined to the inner sleeve, and means on the outer sleeve for rotating the last-named sleeve and through it the inner sleeve in the outer sleeve.

1'7. In a coal mining machine, in combination with a truck and a cutter, an arm for supporting the cutter on the truck, said arm comprising an outer sleeve and an inner sleeve in the outer sleeve, means on the outer sleeve for rotating the inner sleeve with respect to the outer sleeve, and means on the outer sleeve for moving the inner sleeve longitudinally of the outer sleeve.

18. In a coal mining machine, in combination with a truck and a cutter, an arm for supporting the cutter on the truck, said arm comprising an outer sleeve and an inner sleeve in the outer sleeve, means on the outer sleeve for rotating the inner sleeve with respect'to the outer sleeve, and

means on the outer sleeve for moving the inner sleeve longitudinally of the outer sleeve, said first named means including a motor, a sleeve splined to the inner sleeve and an operative connection between the motor and the last-named sleeve.

19. In a coal mining machine, in combination with a truck and a cutter, an arm for supporting the cutter on the truck, said arm comprising an outer sleeve and an inner sleevein the outer sleeve, a third sleeve splined at one end to the inner sleeve and having a gear on its other end, and means on the outer sleeve connected to the gear for rotating the inner sleeve.

20. In a coal mining machine, in combination with a truck and a cutter, an arm for supporting the cutter on the truck, said arm comprising an outer sleeve and an inner sleeve in the outer sleeve, a third sleeve splined at one end to the inner sleeve and having a gear on its other end, means on the outer sleeve connected to the gear for rotating the inner sleeve, and means on the outer sleeve for moving the inner sleeve longitudinally in the outer sleeve.

21. In a coal mining machine, in combination with a truck and a cutter, an arm for supporting the cutter on the truck, said arm comprising an outer sleeve and an inner sleeve in the outer sleeve, means for rotating the inner sleeve in the outer sleeve, means for moving the inner sleeve longitudinally of the outer sleeve, and means journalled in the sleeves for operating the cutter.

22. In a coal mining machine, in combination with a truck and a cutter, an arm for supporting the cutter on the truck, said arm comprising an outer sleeve and an inner sleeve in the outer sleeve, a shaft journalled at one end in the inner sleeve and operatively connected to the cutter, a second shaft journalled at one end in the outer sleeve, said second shaft being hollow to slidably receive the first-named shaft, and means to move the sleeves longitudinally of each other.

23. In a coal mining machine, a truck having arms thereon, a yoke pivoted to said arms on a vertical axis, a sleeve pivoted on said yoke on a horizontal axis, and a motor on the sleeve operatively connected to the yoke for causing the sleeve to swing on its pivot.

24. In a coal mining machine, a truck, a yoke pivoted to the truck, an extensible arm pivoted to the yoke, a motor to swing the yoke on the truck, a motor to swing the arm on the yoke, and a motor to extend the arm.

25. In a coal mining machine, a truck, a cutter head, a telescopic arm to support the head on the truck, said arm having a pivotal connection with the head and with the truck, a cutter bar pivoted on the head, and means on the head to swing the bar.

26. In a coal mining machine, a truck, a cutter head, a telescopic and extensible arm supporting the head on the truck, means to extend the arm, a cutter bar pivoted on the head, a motor on the head to swing the bar, cutting means on the bar, and means on the truck operatively connected to the cutting means for operating it.

27. In a coal mining machine, in combination with a truck, a cutter head, a two-part extensible arm for supporting the cutter head on the truck, and power means on the arm for swinging the arm on the truck, rotating one part of the arm with relation to the other, for extending the arm, and swinging the head on the arm.

28. In a. coal mining machine, in combination 5 with a. truck having arms thereon, a yoke pivotally supported by said arms, said yoke having 

